Importance of Adequately Performed Valsalva Maneuver to Detect Patent Foramen Ovale during Transesophageal Echocardiography - Rodrigues, Ana Clara; Picard, Michael H.; Carbone, Aime; Arruda, Ana Lúcia; Flores, Thaís; Klohn, Juliana; Furtado, Meive; Lira-Filho, Edgar B.; Cerri, Giovanni G.; Andrade, José L. (Journal of The American Society of Echocardiopgraphy, 2013)